0 4

-1

7 6
1 2  6 0 0 -9
1 5 -3 0 0 0
1 2 -10 0 0 15
1 -2 6 0 0 -3
1 -2 -6 0 0 17
1 0 1 -1 0 0
1 1 0 0 -1 0